Psoriasis (cont.)

Gary W. Cole, MD, FAAD

Dr. Cole is board certified in dermatology. He obtained his BA degree in bacteriology, his MA degree in microbiology, and his MD at the University of California, Los Angeles. He trained in dermatology at the University of Oregon, where he completed his residency.

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

What are psoriasis symptoms and signs? What does psoriasis look like?

Psoriasis appears as red or pink areas of thickened, raised, and scaling skin. It classically affects skin over the elbows, knees, and scalp. Although any area may be involved, it tends to be more common at sites of friction, scratching, or abrasion.

Psoriasis may vary in appearance. It often appears as small scaly bumps that coalesce into plaques of raised skin.

Sometimes pulling off one of these small dry white flakes of skin causes a tiny blood spot on the skin. This is medically referred to as a special diagnostic sign in psoriasis called the Auspitz sign.

Finger and toenails often exhibit small pits (pinpoint depressions) and/or larger yellowish-brown separations of the nail from the nail bed at the tip called distal onycholysis. Nail psoriasis may be confused with and incorrectly diagnosed as a fungal nail infection.

Symptoms and signs of plaque psoriasis include polygonal or circular elevated areas (usually at least ½ inch in diameter) of red skin often covered with scale that are likely to be present on the elbows and knees. These may be itchy.

Symptoms and signs of guttate psoriasis include bumps or small plaques (½ inch or less) of red itchy, scaling skin that may be present over large parts of the skin surface. This condition often is preceded by a sore throat and appears all at once.

In inverse psoriasis, genital lesions, especially in the groin and on the head of the penis, are common. Psoriasis in moist areas like the navel or the area between the buttocks (intergluteal folds) may look like flat red plaques. This may be confused with other skin conditions like fungal infections, yeast infections, skin irritation, or bacterial infections.

Symptoms and signs of pustular psoriasis include at rapid onset of groups of small bumps filled with pus on the torso. Patients are often systemically ill and have a fever.

Erythrodermic psoriasis appears as extensive areas of red skin often involving the entire skin surface. Patients may often feel chilled.

Nail psoriasis appears as pits and a yellowish to whitish discoloration at the tip of one or more of the toenails or fingernails. In severe disease, the nails may be fragile and fall apart.

Scalp psoriasis may look like severe dandruff with dry flakes and red areas of skin. It may be difficult to differentiate between scalp psoriasis and seborrheic dermatitis when only the scalp is involved. However, the treatment is often very similar for both conditions.

How do health-care professionals diagnose psoriasis?

The diagnosis of psoriasis is typically made by obtaining information from the physical examination of the skin, medical history, and relevant family history.

Picture of psoriasis on the elbows. Source: Bigstock.com.

Picture of psoriasis on the hands. Source: iStock.com.

Sometimes, lab tests including a microscopic examination of a skin biopsy and X-rays may necessary.